A. Burn it to the ground. The heat will bake the clay tablets into bricks. They’ll outlast any number of civilizations.

Now, that’s my inference, not necessarily the advice of Lionel Casson, professor emeritus of Classics at New York University. But it does give you a glimpse of his book: it’s not only informative, it’s thought-provoking.

This concise history of ancient libraries covers the time from the Sumerians through Greece and Rome to the first medieval monasteries. It describes libraries in terms of architecture, use, contents and influence.

And it brings vividly to life something that might come as a surprise to a modern reader unschooled in — well, okay, largely ignorant of — the history of Antiquity: the library is the most durable institution in the world, more so even than religion.

If Libraries in the Ancient World is any indication, Professor Casson must have been an excellent teacher. You need no prerequisite courses to understand and appreciate the book. Since the study of history is unique in having no jargon, Professor Casson was free to write both readably and with precision. The book would completely engross an intellectually curious high-school student such as myself, if I hadn’t been living in antiquity at the time.

It is nonetheless carefully referenced and indexed in the best tradition of scholarship. And yet, unlike many scholarly works I’ve read — or had to read — over the years, it is not weighted down with tiny-print footnotes. On the contrary, Professor Casson visibly enjoys his subject, witness a quote from the Roman satirist Martial, who indulges in a bit of ironic self-promotion:

This little, slender book, at Tryphon’s store,
Costs just four coppers, and not a penny more.
Is four too much? It puts you in the red?
Then pay him two; he’ll still come out ahead. (p. 104)

And there we enter the realm of surprises. In the First Century, Rome had not only libraries but bookstores? And books? And books were inexpensive? Now that’s an eye-opener.

My inchoate impression of Antiquity is that it was full of barbarians busy mumbling to themselves the mnemonic “Rape, pillage, then burn.” There is something to that; much of the ancient and medieval world resembles the mentality of blighted urban neighborhoods of today: if there’s no prospect of improvement, you may as well steal. Or, if the political system is incoherent, you may as well join a street gang and fight for turf like Roman generals.

What was really going on in the Roman Empire? Wars were the mold on the cake. Scrape it off and we find that literacy was not only widespread, it was common. And there were no restrictions; it was open to all. Some of the graffiti at Pompeii were those of children practicing their ABC’s (p. 109). Even workmen — especially site foremen — would need literacy at some level.

And where most people can read and write, they want something to read. The Great Library at Alexandria was far from the only one in Antiquity; it is just the largest and best known, and the ones in Rome eventually began to rival it. By the Fourth Century, there were libraries all over the Empire.

Libraries were prized for their prestige as well as their practical value. The general Sulla captured Aristotle’s collection in Athens and shipped it to Rome. Actually, Sulla rescued the collection; it had been found in poor condition and was eventually restored by a Greek scholar, Tyrannio (pp. 68-69). For his part, Marc Antony made a present of the library of Pergamum — 200,000 volumes — to Cleopatra, primarily because he knew she’d love it but also because he probably didn’t want to have to maintain it himself (p. 112).

In fact, libraries in Greece and Rome became so big they needed skilled staffs that amounted to a branch of the civil service. And they needed librarians fluent in both Greek and Latin. In “The Arcanus Project,” Pedro B. González has his narrator say, ““Built around A.D. 110 by the emperor Trajan, [the Ulpian] library was interesting because it had separate sections for Greek and Latin works.” That is a little misleading: libraries that had both Greek and Latin works routinely filed them separately, and the Ulpian library was only following long-established custom.

What happened to the ancient libraries? The loss of the library at Alexandria is rightly considered one of the great tragedies of history. But didn’t Muslim scribes preserve a lot of ancient literature?

Well, a lot depends on who your emperor or caliph happened to be. The Great Library itself was probably collateral damage in the bitter fighting in Alexandria in about A.D. 270, when the emperor Aurelian put down a revolt. But a second library, the Serapeum, remained intact. It was razed in A.D. 390, when the hot-headed patriarch Theophilus overzealously carried out the order of emperor Theodosius II to destroy pagan places of worship.

However, the contents of the Serapeum apparently escaped. When Arabs conquered Alexandria in A.D. 642, a Greek asked for the library; but the caliph Omar devoutly refused and decreed a book-burning that, according to legend, took six months to complete (p. 138).

Even with such catastrophes, why was so much lost? Essentially, the medium failed the message. Clay bricks could be used only where they were stored; they were never meant to be lugged around. Papyrus was easy to write on, but the scrolls soon wore out. The codex, the ancestor of the modern book, appeared in Rome in the First Century, and it was by far the most practical to use and carry. However, even though Christians used the new format exclusively for their purposes, its general use spread inexorably but gradually.

What can a reader conclude? What the ancients needed was paper for inexpensive durability, and a printing press for accuracy and mass production. But papermaking would come from China only in the Middle Ages, and the printing press would emerge in Germany only at the dawn of the Renaissance.

The lack of technology was a pity. With paper and printing, the contents of the libraries at Alexandria, Athens, Pergamum and Rome — as well as others — could have covered the Roman Empire like an ancient Internet. And with a society already open to literacy, could political and technological progress have emerged to resist or absorb the barbarian invasions in the west? Or would people have continued to march into the future with their eyes fixed firmly on the past?

And what of today? Writing has evolved from the most durable materials of all — clay and stone — to the most ephemeral: electrons on servers that depend on an entire world civilization to maintain them. The libraries of yesteryear may well again be those of tomorrow.